ABOUT GIS - What is a Geographic Information System?
Geographic Information System (GIS) technology integrates traditional geographic information such as road maps with locations of cities and towns, topography, ground cover, etc. with computing technology. A GIS enables the easy access of geographic information.
Consider a place such as Bar Harbor, Maine, the largest town on Mt Desert Island and neighbor to the popular Acadia National Park. A vast number of maps and documents display various pieces of information about Bar Harbor and Mt Desert Island.
There are driving maps of the area, U.S. Geological Survey (U.S.G.S.) topographic maps, hiking trail maps, maps showing tourism information such as the locations of museums and restaurants, maps of Acadia National Park, NOAA nautical charts of the harbor, U.S. Geological Survey maps of local rock type. Combine these with NASA satellite images from space and specialty maps like historical maps of the Great Fire of 1947 and you have a truly overwhelming list of informational documents about a single town!
A GIS takes all of this information and compiles it into a single database so that a person interested in learning about Bar Harbor, or any place, doesn't have to look at all those individual paper maps.
In a GIS, each map that holds a unique sort of information about a place (population density, land cover, rock type, road locations, streams and lakes, topography, tourist guides, etc.) is treated as its own layer.
All the information on each layer is keyed to its location in degrees of latitude and longitude, allowing different maps to be overlain exactly. Computers allow us to pick a location and access the information about that place held on any map layer in the system. This database can be used to generate new maps that incorporate information from any of the original map layers (for example, overlaying the restaurant map with a topographic map would tell you how good the view is likely to be from each restaurant). This interactive feature of GIS is one of its most powerful features.
